Only the priest is supposed to go to the Tabernacle. According to the GIRM:
- When the distribution of Communion is finished, the priest himself immediately and completely consumes at the altar any consecrated wine that happens to remain; as for any consecrated hosts that are left, he either consumes them at the altar or carries them to the place designated for the reservation of the Eucharist.
As for the EMHCs,the GIRM states that:
These ministers should not approach the altar before the priest has received Communion, and they are always to receive from the hands of the priest celebrant the vessel containing either species of the Most Holy Eucharist for distribution to the faithful.
As for the purifying of the sacred vessels, according to RS:
[119.] The Priest, once he has returned to the altar after the distribution of Communion, standing at the altar or at the credence table, purifies the paten or ciborium over the chalice, then purifies the chalice in accordance with the prescriptions of the Missal and wipes the chalice with the purificator. Where a Deacon is present, he returns with the Priest to the altar and purifies the vessels. It is permissible, however, especially if there are several vessels to be purified, to leave them, covered as may be appropriate, on a corporal on the altar or on the credence table, and for them to be purified by the Priest or Deacon immediately after Mass once the people have been dismissed. Moreover a duly instituted acolyte assists the Priest or Deacon in purifying and arranging the sacred vessels either at the altar or the credence table. In the absence of a Deacon, a duly instituted acolyte carries the sacred vessels to the credence table and there purifies, wipes and arranges them in the usual way.209
Regarding the Communion of the Priest, this is not optional. According to the GIRM:
- After this, standing and turned toward the altar, the priest says quietly, Corpus Christi custodiat me in vitam aeternam (May the Body of Christ bring me to everlasting life) and reverently receives the Body of Christ. Then he takes the chalice, saying quietly, Sanguis Christi custodiat me in vitam aeternam (May the Blood of Christ bring me to everlasting life), and reverently receives the Blood of Christ.
- The Communion chant begins while the priest is receiving the Sacrament (cf. above, no. 86).
I hope this helps.